Abstract:

The optimal removal efficiencies of COD, N and P were investigated by using denitrifying phosphorus activated sludge taken from an anaerobic/anoxic/oxic (A²O)-biological contact oxidation (BCO) system. Response surface methodology using Central Composite Design (CCD) of Design-Expert was used to evaluate the influence and specific function of four important factors (initial COD concentration, nitrate concentration, temperature and anoxic reaction time) on the three responses, which were marked removal rate of COD, N and P as Y_cod, Y_n and Y_p, respectively. Among all the factors, initial COD concentration greatly influenced the three responses. In addition, anoxic reaction time had a major impact on Y_n and temperature had a greater influence on Y_p than other two factors. The three response model equations were all significant, where R² were 0.9853, 0.9118 and 0.9972 respectively. When initial COD concentration, nitrate concentration, temperature and anoxic reaction time were 316.95 mg·L^-1, 42.26 mg·L^-1, 27.19℃, and 237.37 min respectively, the model predictions of Y_cod, Y_n and Y_p were 93.54%, 99.96% and 99.56%, and test responses were 92.03%, 91.15% and 81.64%, respectively.

Key words: denitrifying phosphorus removal, response surface, COD, nitrate, temperature, anoxic reaction time

摘要：

以A²O-生物接触氧化(BCO)工艺系统反硝化除磷活性污泥为研究对象,应用Central Composite Design(CCD)设计考察了起始COD浓度、硝酸盐氮浓度、反应温度和缺氧反应时间对反硝化除磷反应的3个响应值COD去除率(Y_cod)、N去除率(Y_n)和P去除率(Y_p)的影响。结果表明,起始COD对反硝化除磷反应中COD、N和P的去除都有重要影响,且缺氧反应时间对Y_n有较大影响,反应温度对Y_p有很大影响;3个响应值的模型方程均显著,R²分别为0.9853、0.9118和0.9972;当COD为316.95 mg·L^-1、硝酸盐氮为42.26 mg·L^-1、反应温度为27.19℃、缺氧反应时间为237.37 min时,Y_cod、Y_n和Y_p的模型预测值分别为93.54%、99.96%和99.56%,试验响应值分别为92.03%、91.15%和81.64%

关键词: 反硝化除磷, 响应面, COD, 硝酸盐氮, 温度, 缺氧反应时间